Fix Android Style plugin.

Task-number: QTBUG-29565

Change-Id: Iedb861962e3638bcbdf9d9a72a47bebc63b425b9
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>
Reviewed-by: BogDan Vatra <bogdan@kde.org>
Reinitialize system palette when setting a new style.

Task-number: QTBUG-29565

Change-Id: I5ac95d52c453aec9e2160a135dc1afdd9583eed3
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>
Reviewed-by: BogDan Vatra <bogdan@kde.org>
[1/2] Optimize text drawing for QStyleOptionViewItem in QCommonStyle

Optimize isViewItemCached() a bit by reordering conditions so that
conditions that going to change more often in a common case evaluated first.

Change-Id: Ibb406f964345e8f2bff7b433bf33e09a99dcbdc4
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>